// SPDX-License-Identifier: GPL-2.0+
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/*
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* comedi/drivers/8255.c
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* Driver for 8255
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*
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* COMEDI - Linux Control and Measurement Device Interface
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* Copyright (C) 1998 David A. Schleef <ds@schleef.org>
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*/
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/*
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* Driver: 8255
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* Description: generic 8255 support
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* Devices: [standard] 8255 (8255)
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* Author: ds
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* Status: works
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* Updated: Fri, 7 Jun 2002 12:56:45 -0700
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*
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* The classic in digital I/O. The 8255 appears in Comedi as a single
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* digital I/O subdevice with 24 channels. The channel 0 corresponds
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* to the 8255's port A, bit 0; channel 23 corresponds to port C, bit
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* 7. Direction configuration is done in blocks, with channels 0-7,
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* 8-15, 16-19, and 20-23 making up the 4 blocks. The only 8255 mode
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* supported is mode 0.
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*
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* You should enable compilation this driver if you plan to use a board
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* that has an 8255 chip. For multifunction boards, the main driver will
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* configure the 8255 subdevice automatically.
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*
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* This driver also works independently with ISA and PCI cards that
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* directly map the 8255 registers to I/O ports, including cards with
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* multiple 8255 chips. To configure the driver for such a card, the
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* option list should be a list of the I/O port bases for each of the
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* 8255 chips. For example,
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*
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* comedi_config /dev/comedi0 8255 0x200,0x204,0x208,0x20c
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*
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* Note that most PCI 8255 boards do NOT work with this driver, and
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* need a separate driver as a wrapper. For those that do work, the
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* I/O port base address can be found in the output of 'lspci -v'.
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*/
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#include <linux/module.h>
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#include "../comedidev.h"
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#include "8255.h"
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static int dev_8255_attach(struct comedi_device *dev,
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struct comedi_devconfig *it)
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{
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struct comedi_subdevice *s;
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unsigned long iobase;
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int ret;
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int i;
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for (i = 0; i < COMEDI_NDEVCONFOPTS; i++) {
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iobase = it->options[i];
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if (!iobase)
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break;
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}
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if (i == 0) {
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dev_warn(dev->class_dev, "no devices specified\n");
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return -EINVAL;
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}
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ret = comedi_alloc_subdevices(dev, i);
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if (ret)
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return ret;
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for (i = 0; i < dev->n_subdevices; i++) {
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s = &dev->subdevices[i];
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iobase = it->options[i];
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/*
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* __comedi_request_region() does not set dev->iobase.
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*
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* For 8255 devices that are manually attached using
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* comedi_config, the 'iobase' is the actual I/O port
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* base address of the chip.
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*/
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ret = __comedi_request_region(dev, iobase, I8255_SIZE);
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if (ret) {
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s->type = COMEDI_SUBD_UNUSED;
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} else {
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ret = subdev_8255_init(dev, s, NULL, iobase);
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if (ret) {
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/*
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* Release the I/O port region here, as the
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* "detach" handler cannot find it.
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*/
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release_region(iobase, I8255_SIZE);
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s->type = COMEDI_SUBD_UNUSED;
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return ret;
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}
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}
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}
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return 0;
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}
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static void dev_8255_detach(struct comedi_device *dev)
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{
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struct comedi_subdevice *s;
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int i;
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for (i = 0; i < dev->n_subdevices; i++) {
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s = &dev->subdevices[i];
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if (s->type != COMEDI_SUBD_UNUSED) {
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unsigned long regbase = subdev_8255_regbase(s);
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release_region(regbase, I8255_SIZE);
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}
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}
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}
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static struct comedi_driver dev_8255_driver = {
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.driver_name = "8255",
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.module = THIS_MODULE,
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.attach = dev_8255_attach,
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.detach = dev_8255_detach,
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};
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module_comedi_driver(dev_8255_driver);
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MODULE_AUTHOR("Comedi https://www.comedi.org");
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MODULE_DESCRIPTION("Comedi driver for standalone 8255 devices");
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MODULE_LICENSE("GPL");
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